A current trend is the manufacture of an increasing number of electronic and particularly optoelectronic devices on substrates, e.g. in order to provide displays, circuit boards and/or solar cells. In particular, there is an increasing demand for flat display elements such as flat screens. The standards for liquid crystal displays (LCD) and other display elements, in which control elements, for example thin film transistors (TFTs), are used, increase. In addition, the increasing resolution of displays leads to decreasing structure dimensions (critical dimensions) and to a decreased layer thickness which raises the sensitivity for ESD caused defects of such display devices.
The substrate of a flat panel display may be made of glass or of another insulating material. Charges which may accumulate on the surfaces of the substrate during handling and processing of the substrate may lead to an electrical polarization of the substrate. This may increase the risk of damage by electrostatic discharge (ESD) during handling and processing of the substrate. Accordingly, it would be beneficial to protect a substrate from damage which may be caused by electrostatic discharge. Further, charging of a substrate may cause a deterioration of imaging during E-beam Inspection (EBI).
Vacuum Ultraviolet radiation (VUV) aims to eliminate electrostatic charges by directly ionizing residual molecules in a depressurized environment. Vacuum LCD manufacturing equipment, particularly devices utilizing electron beams (SEM, etc.) cannot benefit from conventional ionizers static electricity neutralization because their working mechanism requires a gaseous environment. Further, charge neutralization on large area substrates is difficult with existing radiation sources in light of the size of the substrates.